commit 0f2f3b49365008c35935e90e8caec20470c1f8ac
author Primiano Tucci <primiano@google.com> Tue May 21 19:37:01 2019 +0100
committer Primiano Tucci <primiano@google.com> Tue May 21 19:37:01 2019 +0100
tree 63911cd992666746b517006bc559ccec80e0c6d2
parent 70995c2172982f88c609e34aa71bb02fad7d5393

Stop generating data-source specific C++ classes in tracing/core

We generate C++ classes from proto for a bunch of core classes
like DataSourceConfig, DataSourceDescriptor etc. This is to
prevent spreading protobuf dependencies all over the places.
However, at some point in the past we started adding data-source
specific sub-messages to DataSourceConfig and doing to required
to generate C++ classes for things that don't really belong to
tracing/core (e.g. FtraceConfig, SysStatsConfig, etc).

This CL introduces a decoupling using a proto annotation [lazy=true].
When fields are annotated as such, the generated C++ stub exposes
the field as a raw byte array. This allows to break the dependency
between tracing/core and those configs and pushes the decoding
responsibility to the actual data sources.

This is a step towards getting rid of libprotobuf dependencies
in tracing/core for the client library.
Note that at the moment the generated classes still depend on
libprotobuf for the FromProto / ToProto conversions.

Bug: 132880619
Change-Id: I29751565277e7cb60928571e3eaf513477cf9968